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Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues
Published on: June 3, 2019
Alterations in perivascular adipose tissue structure and function in hypertension
Chao Lu1, Li-Ying Su, Robert M K W Lee
1Smooth Muscle Research Program, McMaster University, Hamilton, Ontario, Canada.
European Journal of Pharmacology
|February 1, 2011
Summary
Hypertension impairs perivascular adipose tissue (PVAT) function in spontaneously hypertensive rats (SHR). This dysfunction reduces PVAT
Area of Science:
- Cardiovascular Biology
- Adipose Tissue Research
- Hypertension Mechanisms
Background:
- Perivascular adipose tissue (PVAT) plays a crucial role in regulating vascular tone.
- Alterations in PVAT structure and function are implicated in cardiovascular diseases like hypertension.
- Spontaneously hypertensive rats (SHR) serve as a model to study hypertension-induced vascular changes.
Purpose of the Study:
- To investigate the structural and functional changes in PVAT of spontaneously hypertensive rats (SHR) compared to normotensive Wistar-Kyoto (WKY) rats.
- To determine the impact of PVAT alterations on vascular contractility and relaxation in hypertension.
- To elucidate the mechanisms underlying PVAT dysfunction in the SHR model.
Main Methods:
- Comparative analysis of body composition and PVAT characteristics (adipocyte density, brown adipocyte content) using dual energy X-ray absorptiometry.
- Functional assessment of isolated blood vessels with varying PVAT and endothelium integrity under phenylephrine stimulation.
- Bioassay experiments to evaluate transferable relaxation factors from PVAT and the effect of angiotensin-(1-7) receptor antagonism.
Main Results:
- SHR exhibited altered body composition with smaller fat mass and greater lean mass than WKY rats.
- Thoracic PVAT in SHR showed increased brown adipocyte density and number, but similar overall PVAT area.
- PVAT from SHR significantly attenuated phenylephrine-induced contraction less than PVAT from WKY rats, indicating impaired inhibitory function.
- Both endothelium-dependent and -independent relaxation components mediated by PVAT were reduced in SHR.
Conclusions:
- PVAT-associated inhibition of vascular contractility is impaired in spontaneously hypertensive rats.
- This functional impairment involves both endothelial and non-endothelial mechanisms within the PVAT.
- The observed PVAT dysfunction in SHR may stem from altered adipocyte composition rather than reduced PVAT mass.
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